Dart APIlicense_detailLicenseDetailPagepackageName packageName property Null safety String packageName final Implementation final String packageName; unself_license_detail license_detail LicenseDetailPage packageName property LicenseDetailPage class Constructors LicenseDetailPage Properties hashCode key packageName runtimeType Methods build createElement debugDescribeChildren debugFillProperties noSuchMethod toDiagnosticsNode toString toStringDeep toStringShallow toStringShort Operators operator ==